Dual purpose valve

[BobbyBaun]

Hi.
I’m installing a hydraulic thumb on a 22 tonne excavator running a 1200 stroke cylinder with 70mm rod, 120mm barrel. I need to fit an inline needle flow control valve with unrestricted reverse flow and also a single acting pilot operated check valve. Reason being is that I have too much flow at 30 LPM and pressure relief set at 2000psi. I need to reduce the flow but have unrestricted reverse flow to avoid pressure intensification in the instance the cylinder is pushed back by the excavator bucket. The check valve is to stop cylinder creep but can only be single acting for the same reason that if the bucket pushes the thumb back theres nothing restricting the thumb cylinder retracting hence avoiding bending the rod.

My question is, is there a valve that serves both of these functions in the market?

I’m not at the machine but from memory it was 1/2 thread or at most 3/4.

Thanks

 

[BobbyBaun]

These are some examples.

 

[Jacc]

What machine is it mounted on?
Inline throttle valves in a hydraulic is like always running full throttle on your car and use the brake pedal to control the speed, it results in excessive heat generation and diesel consumption. There are usually smarter ways to do it, at least you can use a 3-port flow control valve.

 

[BobbyBaun]

I see what your saying and it makes sense. So the 3rd port drains to tank yes?

The machine is an old Samsung 210 1995 model tracked machine. It has An option spool that I’ve plumbed into so I was thinking the reliefs could act as the drain if I were to wind the throttle valve in and reduce flow, it’s not like it’s constantly on just occasionally when I’m actuating the thumb.

Cheers

 

[hydtools]

Yes, the excess flow returns to tank.

Ted